1. Field of the Invention
The invention concerns a method for removing nitrogen oxides and volatile organic compounds, VOC's, from impure air feeding through an incinerator.
2. Description of the Prior Art
Exhaust gases from diesel engines, gas turbines, and many combustion processes contain undesirable amounts of NO.sub.x and VOC's. The environment is now becoming more extensively exposed to the uncontrolled release of these materials into the air. NO.sub.x, for example, contributes to eye irritating smog and to acid rain formation.
By present technology NO.sub.x formation can be reduced simply by lowering the combustion temperature, or by changing process conditions away from the most efficient point, or by similar expensive procedures. There are costly processes for injecting ammonia into flue gas at a particular temperature. Selective reduction catalysts are available, but they do not also remove VOC's and residual ammonia. U.S. Pat. No. 4,087,250 uses gaseous ammonia for exothermic reaction with nitric oxides in the exhaust gas as it passes through catalyst beds. U.S. Pat. Nos. 4,188,364, 4,246,234, and 4,571,329 each concern a method of reducing nitrogen oxide by reaction over a catalyst. U.S. Pat. No. 4,878,442 concerns a method of removing nitrogen oxides from waste gas by igniting the oxides with carbonaceous material in the presence of air.
It is therefore an object of the present invention to provide a method that overcomes the disadvantages of conventional methods for removing nitrogen oxides from impure air.
This and other objects, features and advantages of the invention will be apparent from the accompanying drawing FIGS. 1 and 2 and the following description.